Opt-in is only meaningful if users can make an informed decision. I think explaining a system like PPA would be a difficult task. And most users complain a lot about these types of interruption. In my opinion an easily discoverable opt-out option + blog posts and such were the right decision
https://neuromatch.social/system/media_attachments/files/112/784/524/710/147/821/original/d6fe628916b59f77.png